These 30 metropolises have adopted local ordinances that are tougher than state smoking bans in many cases, making bars, restaurants and workplaces smoke-free, CDC director Thomas Frieden said in a Nov. 16 report.

The CDC said the top 50 U.S. cities have gone from 2% smoke-free in 2000 to 60% smoke-free today.

Of the 20 largest cities that still permit some smoking, several -- such as Los Angeles and Atlanta -- are covered by less rigorous statewide bans, the agency said.

Frieden said going 100% smoke-free in the remaining 20 largest U.S. cities would reduce cancer and heart disease for 16 million people.

The CDC said 10 states have laws that prevent local governments from passing antismoking restrictions.